1. Field
The following description relates to a main hub, a sub hub, and a sensor node communicating in a wireless body area network (WBAN) including at least one sub hub, and a communication method thereof.
2. Description of Related Art
To minimize power consumption and system complexity, a wireless body area network (WBAN) based on the Institute of Electrical and Electronics Engineers (IEEE) 802.15.6 standard may provide only a star topology in which sensors are connected to a hub. In a WBAN, a hub may operate the WBAN through a medium access control, a power control, and a beacon transmission for time synchronization.
Communication devices equipped with a WBAN communication protocol and an Internet and cellular access function, such as, for example, a mobile phone, may be used as a hub of a WBAN. However, in the daily life of a user, a hub may be absent. Accordingly, a WBAN may not be appropriately controlled whereby a signal may not be received from a sensor node of the WBAN.
For example, a low-power WBAN may constrain a transmission power of a sensor node to increase a lifetime of the sensor node. Accordingly, a communicable transmission and reception distance between a hub and the sensor node may be constrained. If a line of sight (LoS) between the hub and the sensor node is not secured, the communication performance may be further degraded. In addition, with respect to a sensor node, a memory storage capability may be limited in order to decrease power consumption, hardware complexity, and production costs. Accordingly, it may be impossible to store sensor data for a long period of time while the hub is absent.